X-ray vs. NMR structure of N-terminal domain of δ-subunit of RNA polymerase.
J Struct Biol
; 187(2): 174-186, 2014 Aug.
Article
em En
| MEDLINE
| ID: mdl-24937760
ABSTRACT
The crystal structure of the N-terminal domain of the RNA polymerase δ subunit (Nδ) from Bacillus subtilis solved at a resolution of 2.0Å is compared with the NMR structure determined previously. The molecule crystallizes in the space group C222(1) with a dimer in the asymmetric unit. Importantly, the X-ray structure exhibits significant differences from the lowest energy NMR structure. In addition to the overall structure differences, structurally important ß sheets found in the NMR structure are not present in the crystal structure. We systematically investigated the cause of the discrepancies between the NMR and X-ray structures of Nδ, addressing the pH dependence, presence of metal ions, and crystal packing forces. We convincingly showed that the crystal packing forces, together with the presence of Ni(2+) ions, are the main reason for such a difference. In summary, the study illustrates that the two structural approaches may give unequal results, which need to be interpreted with care to obtain reliable structural information in terms of biological relevance.
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Base de dados:
MEDLINE
Assunto principal:
Conformação Proteica
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RNA Polimerases Dirigidas por DNA
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Cristalografia por Raios X
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Ressonância Magnética Nuclear Biomolecular
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
República Tcheca